We have experimentally investigated the viscosity of nematic liquid crystal mixtures of p-methoxybenzylidene-p′-n-butylaniline (MBBA) and p-ethoxybenzylidene-p′-cyanoaniline (EBCA) in the presence of electroconvection under an ac electric field with 60 Hz. Although the viscosity of the mixtures with negative dielectric anisotropy shows a characteristic decrease in the high-voltage regime, that with positive dielectric anisotropy shows a monotonic increase as the applied voltage is increased. The experimental results suggest that the decrease in viscosity observed only for the mixtures with negative dielectric anisotropy is attributed to the negative contribution of electric stress caused by the anisotropic director distribution of the turbulent state.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)